In hydrogen blower applications, it is desirable to package a drive unit and a compressor unit within a single housing. Further, it is desirable that the drive unit be capable of selectively driving the compressor unit in response to system load. Further yet, it is desirable that the drive unit and compressor unit are disposed in separate chambers within the housing to effectively seal the drive unit from the compressor unit. To that end, a sealing system disposed between the drive unit chamber and the compressor unit chamber plays a significant role.
Typically, a hydrogen blower is used within a fuel cell system or in a hydrogen storage application such as at a hydrogen station or the like to supply a stream of compressed hydrogen to a fuel cell stack. In a typical fuel cell system, a hydrocarbon fuel is processed in a fuel processor, for example, by reformation and partial oxidation processes, to produce a reformate gas which has a relatively high hydrogen content on a volume or molar basis. This hydrogen gas is fed through an anode chamber of a fuel cell stack. At the same time, oxygen in the form of an air stream is fed into a cathode chamber of the fuel cell stack. The hydrogen from the reformate stream and the oxygen react in the fuel cell stack to produce electricity. To maintain a constant and consistent stream of hydrogen supply to the fuel cell stack, a hydrogen blower is typically provided between the reformation process and the fuel cell stack.
Conventional hydrogen blower systems, compress and store hydrogen within a housing due to the interaction of a drive unit and a compressor unit. Specifically, a conventional drive unit such as an electric motor is disposed within the housing and includes a drive shaft fixedly attached to the compressor unit to selectively drive the compressor unit in response to a system load. Typically, the compressor unit includes a series of impellers, whereby the impellers compress the hydrogen due to the rotation of the drive shaft and the interaction of the air flow therein. In this manner, the compressed hydrogen is typically stored within the housing and may be selectively released when needed. Releasing of the compressed hydrogen governs the system load as more hydrogen will need to be compressed as the housing is drained, thus regulating the rate and frequency at which the drive unit rotates the impellers.
To ensure that the hydrogen blower maintains a high efficiency, a seal is commonly disposed between the drive unit and the compressor unit. The seal serves to keep the compressed hydrogen separate from the drive unit in an effort to maintain the efficiency of the compressor. As can be appreciated, any loss of hydrogen between the compression unit and the drive unit results in an overall loss in blower efficiency. Conventional sealing systems commonly include a flexible member or ring such as a rubber gasket, or the like, disposed between the drive unit and the compressor unit. The gasket is commonly fixedly attached to the drive shaft for rotation therewith and forms a barrier between the drive and compression units.
While adequately preventing the hydrogen from passing from the compression unit to the drive unit, the conventional sealing systems can be complex, expensive to manufacture, and create a relatively large amount of frictional resistance.
Therefore a hydrogen blower that provides a drive unit operable to drive a compressor unit disposed within a common housing, while maintaining a seal between the drive unit and the compressor unit, is desirable in the industry. Additionally, providing a seal between the drive unit and a compressor unit that improves and maintains high efficiency is also desirable.